1. Field
The present disclosure relates to displays, and more particularly, to micro-lenses capable of changing focal length, micro-lens arrays including the same, 3D displays including the micro-lens arrays and methods of operating the 3D displays.
2. Description of Related Art
A 3D image may be displayed in various ways. An example display method is a glass-type method that uses a shutter or polarized light. The glass-type method, however, is limited in the number of viewpoints that it creates. In addition, a 3D image is displayed mainly with stereoscopic techniques, and thus, a viewer's eyes get tired easily.
Another example display method is a holographic display method. This method may generate a natural 3D image using a wavefront generation method. However, the holographic display method uses a laser source that has a high coherence. The lasers that are used as light sources are very limited. Also, there is a noise problem, such as speckle noise on a display surface on which an image is displayed and also a problem in that an image size and a viewing angle may be limited.
Another example display method is an integrated image method that uses a lens array. The integrated image method has advantages in that realization of color is easy, consecutive viewing angles may be secured, and an optical system may be simplified. In addition, the integrated image method may be used in high performance cameras and charge-coupled devices.
However, because the integrated image method uses a micro-lens array, an integrated image may be limited. Also, there is a limit in the depth and viewing angle of a 3D image that is generated through the micro-lens array.